(a) Field of the Invention
The present invention relates to an apparatus and method for transmitting/receiving a signal in inband full duplex system.
(b) Description of the Related Art
An inband full duplex (IFD) scheme is a technique of receiving a signal, while simultaneously transmitting a signal in the same frequency band at the same time, which is able to theoretically double wireless capacity at the maximum, compared with a half duplex (HD) scheme currently employed in wireless communication systems.
FIG. 1 is a conceptual view illustrating an HD system.
Referring to FIG. 1, a node of an HD system transmits and receives a signal at a distributed time or through a distributed frequency, that is, uses a different time or frequency resource in transmitting and receiving a signal, and thus, it is easy to maintain orthogonality of transmitted and received signals. However, in the HD system, if a different time or frequency resource is used for signal transmission and reception, double the resource may be consumed, compared with an inband full duplex (FD) system. In particular, as a solution to inefficiency of the HD system, in an IFD system, a node may simultaneously (that is, the same time resource) transmit and receive in the same band (that is, the same frequency resource). The IFD system may theoretically double link capacity at the maximum, compared with an HD system. The IFD scheme is a technique requisite for attaining a goal of increasing traffic capacity of small wireless devices such as smartphones to 1000 folds as pursued in 5th-generation (5G) mobile communication.
However, in order to realize such an IFD system, a self-interference signal needs to be canceled. That is, a signal (self-transmission signal) transmitted in a transmission/reception device of an IFD system may be easily introduced to a receiver, and thus, the self-transmission signal may act as strong self-interference on a valid reception signal. A technique for canceling such self-interference is a self-interference cancellation (SIC) technique.